1. Field of the Invention
The invention generally relates to optical lens, in particular, to optical imaging lens.
2. Description of Related Art
The specification of the consumer electronic products, such as mobile phone, camera, tablet computer, personal digital assistant, car video apparatus et al., are ever-change. In addition, the pace for pursuit of short and light products is never slowed down. Therefore, the critical elements of the electronic products such as the optical element and so on, need to be continuously improved in specification to satisfy the requirement of consumer. The essential features of the optical lens are nothing more than the imaging quality and the volume. To the feature of imaging quality, as the development of image sensing technology, consumers accordingly require more for the imaging quality. Therefore in the field of designing the optical lens, in addition to the pursuit of thin lens, the imaging quality and performance of the lens should be also taken into account. in order to meet the demand for imaging on relatively distant objects or close objects, the conventional optical lens is usually implemented with voice coil motor (VCM), then the VCM can be used to adjust the location of the image plane so as to achieve the capability for auto focusing.
However, the design of optical lens is not simply scaling down the lens with good imaging quality so to produce the optical lens having both imaging quality and miniaturization. The designing procedure not only involves the material properties, but also considers the practical issues of production in fabrication, assembly yield and so on. The manner to achieve auto focusing by using the VCM to adjust the location of the image plane would cause the increase of lens length during the operation of VCM. Therefore, it has long been the sophistication goal for industry, government, and academia about how to fabricate the optical lens satisfying the requirements for the consumer electronic products and continuously improve the imaging quality.